This study investigated the role of knowledge base organization in elementary school students' memory performance. In a preliminary study, students in grades 2, 6, and 10 rated words from three semantic categories for their category representativeness. Results disclosed age-related changes in how children rate words for high and low typicality. Based on the students' ratings, a 24-word list of words of high and low typicality was constructed for each grade level. These word lists subsequently were used in a multitrial free recall memory study. Within each of the three grades, 16 subjects studied and recalled grade 2 level words, 16 studied and recalled grade 6 level words, and 16 studied and recalled grade 10 level words. Analysis of variance was performed on recall scores, category clustering scores, and subjective organization scores. It was found that subjects in grades 6 and 10 organized age-appropriate word lists best. For less typical, but not highly typical words, recall and organization was best for the grade 2 words, followed by the grade 6 and grade 10 words. Findings also revealed that memory organization increased over trials only for the older subjects. The research indicates that age-appropriate word norms are important in investigations of children's memory development. However, the knowledge base accounts for only some age differences in memory organization and recall performance. (Author/RH)